For example, in order to correct variations in the amount of fuel injected via fuel injection valves of a diesel engine, the injection durations needed for a target amount of injection corresponding to various values of fuel pressure are measured at a plurality of points beforehand with regard to each fuel injection valve. Deviations of the injection duration from that of a standard fuel injection valve are determined as correction values. The correction values are coded in a two-dimensional manner, and are then attached to fuel injection valves, which are transported to a section of assembling a diesel engine.
When fuel injection valves are mounted to the individual cylinders at the assembly section, the content of the two-dimensional code attached to each fuel injection valve is read, and the obtained correction values are arranged in the form of a map with parameters of fuel pressure and injection duration. The map is stored in a memory provided in an ECU (electronic control unit), and will be used for the fuel injection amount control of the fuel injection valves.
Performance requirements for fuel injection valves vary in accordance with the kinds of diesel engines to be assembled. In accordance with various requirements, various types of fuel injection valves having different characteristics exist. Due to such different characteristics, the correction values-based maps of different kinds of fuel injection valves may differ from one another in terms of a region where high-precision control is possible although correction points are provided at low density, and a region where if correction points are not provided at high density, a great deviation in control will result and high-precision control will be impossible.
Considering cases where the region where correction points may be provided at low density and the region where correction points need to be provided at high density vary depending on kinds of fuel injection valves, it is necessary to provide correction points with high density in the whole spaces of fuel pressure and injection duration.
However, the information record medium attachable to a fuel injection valve, such as a two-dimensional code or the like, has only a limited capacity for recording information, and therefore cannot store a great number of correction values corresponding to high-density correction points so as to be applicable to all kinds of fuel injection valves.
Even if an information record medium capable of storing many correction values is available, there still is a need to measure various data and determine correction values beforehand. Furthermore, when a fuel injection valve is mounted in a diesel engine after many correction values have been stored in an information record medium, it is necessary to read many correction values from the information record medium and store them into a memory of an ECU. Therefore, there is a danger of cost increases in both apparatuses and assembling operations.
The problems stated above occur with regard to not only the fuel injection valves of diesel engines, but also the fuel injection valves of other types of engines, and occur in management and control of actions of other mechanisms, for example, correction of values detected by various sensors, and the like.